Bluetooth is a radio technology which supports short-range communication of a device, with a general communication distance of within 10 m, and Bluetooth can carry out wireless information exchange in between numerous devices including mobile telephone, PDA, wireless headphone, notebook computer, related peripherals, and the like. With the Bluetooth technology, communications in between mobile communication terminal devices can be simplified effectively, and communications between the devices and the Internet can also be simplified successfully, thereby making data transmission more prompt and efficient, which widens the path for wireless communications.
Bluetooth adopts a distributed network structure as well as a fast frequency hopping and short-packet technology, supports point-to-point and point-to-multipoint communications, operates at a global general Industrial Scientific Medical (ISM) frequency band of 2.4 GHz, has a data rate of 1 Mbps, and adopts a time division duplex transmission scheme to achieve a full-duplex transmission. Wherein, in a Bluetooth protocol stack, a Service Discovery Protocol (SDP), also referred to as a Bluetooth SDP, is used for providing specific meaning of an application program in a Bluetooth environment, and for discovering which service is available and deciding characteristics of the available service. SDP defines a method for a Bluetooth client to discover an available Bluetooth server service and characteristics, in which Bluetooth service attributes are as shown in Table 1:
TABLE 1attribute identifierType of attribute valueServiceRecordHandle<int>ServiceClassIDList<DES>ServiceID<UUID>ProtocolDescriptorList<DES>or<DEA>BrowseGroupList<DES>
SDP adopts a client/server model and a request/response mechanism, as shown in FIG. 1, where a service record is saved on a sever, a client initiates a transaction via a request Protocol Data Unit (PDU), and the server returns a response PDU to respond the request.
Each SDP PDU includes a PDU header and PDU-specific parameter/parameters; the PDU header includes three domains: a PDU Identifier (PDU ID), a Transaction ID, and a Parameter Length, specifically as shown in FIG. 2. Wherein, the PDU ID is used to distinguish the type of a PDU, so as to determine the meaning of the PDU and parse a parameter thereof. A specification for the PDU ID and its corresponding value is as described in Table 2;
TABLE 2ValueSpecification0x00Reserve0x01SDP_ErrorResponse0x02SDP_ServiceSearchRequest0x03SDP_ServiceSearchResponse0x04SDP_ServiceAttributeRequest0x05SDP_ServiceAttributeResponse0x06SDP_ServiceSearchAttributeRequest0x07SDP_ServiceSearchAttributeResponse0x07-0xFFReserve
The Transaction ID is used to distinguish different request PDUs. When a response PDU is received, it is determined whether the response PDU is the response to a corresponding request PDU according to the Transaction ID of the response PDU, with the following specific determining principle: an SDP client selects an arbitrary value different from the Transaction ID of an existing request PDU as the Transaction ID of a request PDU, and the Transaction ID contained in a response PDU must be the same as the Transaction ID of its corresponding request PDU. The Parameter Length field denotes the overall length (in bytes) of parameters carried in this PDU.
Radio Frequency Identification (RFID) is a non-contact automatic identification technology, which automatically identifies a target object and acquires the related data through a radio frequency signal. The identification operation needs no manual intervention, and may operate under various harsh environments. The RFID technology may identify a fast-moving object, and may identify multiple tags at the same time, and it is fast and convenient to operate. The RFID is a simple wireless system, which generally consists of at least one interrogator (or reader) and multiple transponders (or tags). The system is usually used to control, detect, and track an object.
Information interaction between a communication terminal and a constantly varying environment may change and improve people's life style and quality of life, and the technologies of Bluetooth and RFID are two choices of great potential. Bluetooth may carry out information interaction with other devices within an effective range, thereby achieving the purpose of gathering information or issuing an order. However, there is a defect in a Bluetooth connection mode commonly used at present, i.e., it requires to go through a Bluetooth device inquiry and a service inquiry every time before establishing a Bluetooth connection, and it will cost more than ten seconds or even twenty or thirty seconds to complete the above mentioned inquiry; besides, the above mentioned inquiry also requires human participation. Therefore, the Bluetooth connection mode commonly used at present cannot well satisfy the requirement of concise and rapid connection in the communication terminal and the constantly varying environment.